FIELD OF THE INVENTION
[0001] The invention relates to the use of dialkylmalamides to reduce the surface tension
in water-based systems.
BACKGROUND OF THE INVENTION
[0002] The ability to reduce the surface tension of water is of great importance in waterborne
coatings, inks, adhesives, fountain solutions and agricultural formulations because
decreased surface tension translates to enhanced substrate wetting in actual formulations.
Surface tension reduction in water-based systems is generally achieved through the
addition of surfactants. Performance attributes resulting from the addition of surfactants
include enhanced surface coverage, fewer defects, and more uniform distribution. Equilibrium
surface tension performance is important measure of the ability of a surfactant to
reduce surface tension in aqueous systems when the system is at rest.
[0003] Traditional nonionic surfactants, such as alkylphenol or alcohol ethoxylates and
ethylene oxide (EO)/propylene oxide (PO) copolymers, and anionic surfactants, such
as sodium dialkyl sulfosuccinates, have good equilibrium surface tension performance.
However, many of these surfactants are foamy and this can lead to problems in applications
such as coatings, inks, adhesives, fountain solutions, agricultural formulations,
electronic chemicals and cleaning formulations, and other applications where foam
can lead to surface defects, poor adhesion, and processing difficulties. Additionally,
anionic surfactants can impart water sensitivity to the finished coating.
[0004] In addition to the development of high-performance surfactants, there is considerable
interest in the industry in surfactants with improved environmental characteristics.
Environmental concerns have led to an increased use of environmentally compatible
surfactants as alternatives have become available. In addition, the use of less favorable
products, such as alkylphenol ethoxylate (APE) surfactants, has declined. This is,
in part, due to the poor environmental characteristics of APE surfactants, such as
incomplete biodegradation and a suspicion that they may function as endocrine mimics.
The demand for high-performance, eco-friendly surfactants has stimulated efforts in
new surfactant development. From this work a new family of surfactants, referred to
as alkyl polyglycoside (APG) surfactants, has emerged as a readily biodegradable,
environmentally-friendly alternative to conventional surfactants. These materials
can be foamy and thus are not suitable for many coating, ink, adhesive, fountain solution,
agricultural, and electronic chemical and cleaning applications where the generation
of foam is undesirable.
[0005] Thus, not only is it desirable to obtain surfactants which exhibit excellent surface
tension reducing capabilities and low foam, but it is also highly desirable that such
new surfactants are environmentally-friendly. Moreover, since there is substantial
interest in the development of environmentally-friendly surfactants, an essential
attribute would be that these new surfactants not only possess the aforementioned
desired performance properties but also are derived from naturally occurring compounds
or their synthetic equivalents.
[0006] The importance of reducing surface tension in applications such as coatings, inks,
adhesives, agricultural formulations, and electronic chemical and cleaning is well-appreciated
in the art. The ability to lower the surface tension of aqueous media without producing
foam is critical when one wants to wet low energy or contaminated substrates. In J.
C. Padget's article entitled "Additives for Water-based Coatings - A Polymer Chemist's
View" in
Additives for Water-based Coatings, D. R. Karsa, ed., Cambridge, UK: Royal Society of Chemistry, 1990, pp. 1-29, the
importance of surfactants in lowering the surface tension of aqueous systems in order
to achieve wetting on low energy materials such as plastics and oily steel is highlighted.
[0007] In the graphic arts, it is well-known that surfactants lower the surface tension
of aqueous media and thus aid in printing on lower energy substrates such as plastics,
coated papers, coated cardboards, and foils and in wetting pigments to produce dispersions.
In
Dispersions: Characterization, Testing, and Measurement, Marcel Dekker, Inc., 1990, there is an entire chapter devoted to the topic of wettability
and the necessity of lowering surface tension in order to achieve displacement of
air from around small pigment particles and allow wetting and spreading on the pigment
surface. Surfactants are known to act as wetting agents to moisten hydrophobic areas
of the printing plate in offset printing (R. Kubler, "Printing Inks," in
Ullmann's Encyclopedia of Industrial Chemistry, Vol. A22, 1993, pp. 143-156), and certain surfactants have been beneficial in reducing
foam generation in the ink fountain in flexographic and rotogravure printing inks
(R. W. Bassemir,
et al., "Inks," in
Kirk-Othmer Encyclopedia of Chemical Technology, 4
th Edition, Vol. 14, pp. 482-503).
[0008] In addition, the demands of the semiconductor fabrication industry have led to the
requirement for high performance surfactants and wetting agents for photoresist developer
formulations. As line features shrink to smaller sizes and photoresist substrate materials
become more aliphatic in nature (i. e., lower surface energy), aqueous developer solutions
increasingly are being formulated with surface tension reducing agents. An additional
requirement for these developers, accentuated by the move toward larger wafer sizes,
is that they exhibit low foam. This is particularly important when the so-called spray
puddle techniques are used in applying the developer solution, wherein the developer
is sprayed over increasingly larger areas. Even in cases where puddle or immersion
techniques are used, microbubble entrainment during spreading of the solution over
the photoresist surface can lead to defects. Other applications in the electronics
industry using aqueous processing media would also benefit from good wetting and low
foam.
[0009] Tetramethylammonium hydroxide (TMAH) is the chemical of choice in aqueous alkaline
solutions for developing photoresists according to
Microlithography, Science and Technology, J. R. Sheats and B. W. Smith, editors, Marcel Dekker, Inc., 1998, pp. 551-553. Surfactants
are added to the aqueous TMAH solutions to reduce development time and scumming and
to improve surface wetting.
[0010] A few examples of amides of malic acid (2-hydroxybutanedioic acid), also called malamides,
are known. L-Malic acid occurs naturally as the predominant acid in many fruits, including
apples, persimmons, quince and watermelons. It is classified as GRAS (Generally Recognized
As Safe) by the U.S. Food and Drug Administration and is commonly used as a food acidulant.
L-Malic acid is produced commercially from aqueous fumaric acid using immobilized
Brevibacterium flavum cells in carrageenan. The racemic form, DL-malic acid, is also known. It is produced
by hydration of maleic acid at elevated temperature and pressure.
[0011] In the literature, malic acid amides have been reported. However, the ability of
malamides to lower surface tension in aqueous media has never been studied or realized.
[0012] Dermer and George,
Proceedings of the Oklahoma Academy of Science, 1972, 52, pp. 66-69, describe the preparation of several malamides via reaction of the
malate esters with primary amines. Malamides based on ethyl, isopropyl, cyclohexyl,
hydroxyethyl and benzyl amines were isolated and characterized.
[0013] DE 4424533 A1 broadly discloses oligohydroxy dicarboxylic acid derivatives, including
certain malamides derived from fatty alkyl amines, as synthetic barrier lipids in
skin care products.
[0014] US 5,359,129, discloses many malic acid derivatives, specifically including the acetate
of lauryl malamide, and methods for treatment of psoriasis using such compositions.
[0015] US 5,776,494 discloses the use of alkyl amides of di- and tri-carboxylic acids as
gelling agents in non-aqueous pharmaceutical compositions.
SUMMARY OF THE INVENTION
[0016] This invention provides water-based compositions containing an organic or inorganic
compound, particularly aqueous organic coating, ink, adhesive, fountain solution,
agricultural and electronics cleaning compositions, having reduced surface tension
by incorporation of an effective amount of an N,N'-dialkylamide of malic acid, herein
referred to as a malamide, of the following structure:

where R
1 and R
2 are C4 to C10 alkyl groups, and preferably at least one of R
1 and R
2 is a branched C4 to C10 alkyl group. It is also desirable that an aqueous solution
of the malamide demonstrate an equilibrium surface tension of less than 52 dynes/cm
at a concentration of no more than 5 wt% in water at 25°C using the Wilhelmy plate
method. The Wilhelmy plate method of measuring surface tension is described in L.
Wilhelmy's article in
Ann. Phys. 1863,
119, 177, which is incorporated by reference.
[0017] By "water-based", "aqueous" or "aqueous medium", we mean, for purposes of this invention,
a solvent or liquid dispersing medium which comprises at least 90 wt%, preferably
at least 95 wt%, water. Obviously, an all water medium is also included.
[0018] Also provided is a method for lowering the equilibrium surface tension of such aqueous
compositions by the incorporation of these malamide compounds.
[0019] Also provided is a method for applying a coating of a water-based inorganic or organic
compound-containing composition to a surface to partially or fully coat the surface
with the water-based composition, the composition containing an effective amount of
a malamide compound of the above structure for reducing the equilibrium surface tension
of the water-based composition.
[0020] There are significant advantages associated with the use of these malamides in water-based,
organic-compound containing compositions, such as water-based coatings, inks, adhesives,
fountain solutions, agricultural formulations, and electronic chemical and cleaning
formulations, including photoresist developer compositions, and these advantages include:
- water-borne coatings, inks, adhesives, fountain solutions, agricultural formulations,
and electronic chemical formulations which may be applied to a variety of substrates
with excellent wetting of substrate surfaces;
- a reduction in coating or printing defects such as orange peel and flow/leveling deficiencies;
- low surface tension aqueous electronics cleaning and processing solutions, including
photoresist developer solutions, which provide good wetting and very low foam;
- low-foam surfactants capable of reducing surface tension;
- water-borne compositions using a surfactant derived from natural, renewable resources,
thus making such formulations environmentally favorable.
[0021] Because of their surfactant properties and the ability to control foam, these materials
are likely to find applicability in many applications in which the reduction in surface
tension and low foam are important. Such applications in which low foam is important
include various wet-processing textile operations, such as the dyeing of fibers, fiber
scouring, and kier boiling, where low-foaming properties would be particularly advantageous;
they may also have applicability in soaps, water-based perfumes, shampoos, detergents,
cosmetics and food processing where their marked ability to lower surface tension,
and at the same time produce substantially no foam would be highly desirable.
DETAILED DESCRIPTION OF THE INVENTION
[0022] This invention relates to the use of N,N'-dialkylamide compounds of the structure:

where R
1 and R
2 are C4-C10 alkyl groups, and preferably at least one of R
1 and R
2 is a branched C4 to C10 alkyl group, preferably C5 to C10, and most preferably C5
to C8, for the reduction of equilibrium surface tension in water-based compositions
containing an organic compound, particularly coating, ink, fountain solution, adhesive,
agricultural, and photoresist developer compositions containing organic compounds
such as polymeric resins, detergents, herbicides, fungicides, insecticides or plant
growth modifying agents. It is also desirable that an aqueous solution of the malamide
demonstrate an equilibrium surface tension of less than 52 dynes/cm at a concentration
of 5 wt% or less in water at 25°C using the Wilhelmy plate method.
[0023] In one aspect of the invention the malamides of the above formula display excellent
ability to reduce equilibrium surface tension while producing little to no foam.
[0024] These materials may be prepared by the reaction of primary amines with malic acid
or malic acid esters. The reaction is illustrated below:

[0025] The amination reaction may be performed using a variety of conditions as described
in the
Kirk-Othmer Encyclopedia of Chemical Technology, 4
th Ed., Vol. 2, pp. 348-351. The preferred method involves the reaction of a malic acid
ester with 2 or more equivalents amine in a protic solvent.
[0026] All primary amines or mixtures of primary amines containing at least one C4 to C10
branched alkyl amine may be utilized for the preparation of the N,N'-dialkyl-malamides
of this invention, with amines containing 5-10 carbons being preferred and those containing
5-8 carbons being especially preferred. The N,N'-dialkylmalamides may contain a total
of 8-20 amide alkyl carbon atoms, with those containing a total of 10-20 amide alkyl
carbons being preferred and those containing a total of 10-16 amide alkyl carbons
being especially preferred. Alkyl groups which are suitable should have sufficient
carbon to confer surface activity (
i.e. an ability to reduce the surface tension of water) to the material but not enough
carbon to decrease the solubility to the extent that the ability of the material to
reduce surface tension is insufficient for a particular application. Generally, in
the practice of this invention, it is desirable to choose amide alkyl groups such
that the resulting N,N'-dialkylmalamides have a solubility that affords the desired
surface tension reduction.
[0027] The alkyl groups in the malamides of this invention may be the same or different
and may be linear or branched, as long as at least one of the alkyl groups is a branched
alkyl group. Examples of suitable branched alkyl groups are isobutyl,
sec-butyl, 2-pentyl, 3-pentyl, isopentyl, neopentyl, 2-methylbutyl, 3-methyl-2-butyl,
2-hexyl, 3-hexyl, 2-ethylbutyl, 4-methyl-2-pentyl, 2-ethylhexyl, and so on. Of the
malamide derivatives those which contain a total of 10 to 20 amide alkyl carbons are
preferred and those containing 10 to 16 alkyl carbons most preferred, especially in
the cases where R
1 = R
2 = isopentyl and where R
1 = R
2 = 2-ethylhexyl.
[0028] An amount of dialkylmalamide compound that is effective to reduce the equilibrium
surface tension of the water-based, inorganic or organic compound-containing composition
is added. Such effective amount may range from 0.001 to 20 wt%, preferably 0.01 to
10 wt%, and most preferably 0.05 to 5 wt%, of the aqueous composition. Naturally,
the most effective amount will depend on the particular application and the solubility
of the malamide.
[0029] The dialkylmalamides are suitable for use in an aqueous composition comprising in
water an inorganic compound which is a mineral ore or a pigment or an organic compound
which is a pigment, a polymerizable monomer, such as addition, condensation and vinyl
monomers, an oligomeric resin, a polymeric resin, a detergent, a caustic cleaning
agent, a herbicide, a fungicide, an insecticide, or a plant growth modifying agent.
[0030] In the following water-based organic coating, ink, adhesive, fountain solution, agricultural
and photoresist developer compositions containing a dialkylmalamide according to the
invention, the other listed components of such compositions are those materials well
known to the workers in the relevant art.
[0031] A typical water-based protective or decorative organic coating composition to which
the dialkylmalamide surfactants of the invention may be added would comprise in an
aqueous medium 30 to 80 wt% of a coating composition containing the following components:
Water-Based Organic Coating Composition |
0 to 50 wt% |
Pigment Dispersant/Grind Resin |
0 to 80 wt% |
Coloring Pigments/Extender Pigments/Anti-Corrosive Pigments/Other Pigment Types |
5 to 99.9 wt% |
Water-Borne/Water-Dispersible/Water-Soluble Resins |
0 to 30 wt% |
Slip Additives/Antimicrobials/Processing Aids/Defoamers |
0 to 50 wt% |
Coalescing or Other Solvent |
0.01 to 10 wt% |
Surfactant/Wetting Agent/Flow and Leveling Agents |
0.01 to 5 wt% |
Dialkylmalamide |
[0032] A typical water-based ink composition to which the dialkylmalamide surfactants of
the invention may be added would comprise in an aqueous medium 20 to 60 wt% of an
ink composition containing the following components:
Water-Based Ink Composition |
1 to 50 wt% |
Pigment |
0 to 50 wt% |
Pigment Dispersant/Grind Resin |
0 to 50 wt% |
Clay base in appropriate resin solution vehicle |
5 to 99.9 wt% |
Water-Borne/Water-Dispersible/Water-Soluble Resins |
0 to 30 wt% |
Coalescing or Other Solvent |
0.01 to 10 wt% |
Surfactant/Wetting Agent |
0.01 to 10 wt% |
Processing Aids/Defoamers/Solubilizing Agents |
0.01 to 5 wt% |
Dialkylmalamide |
[0033] A typical water-based agricultural composition to which the dialkylmalamide surfactants
of the invention may be added would comprise in an aqueous medium 0.1 to 80 wt% of
an agricultural composition containing the following components:
Water-Based Agricultural Composition |
0.1 to 50 wt% |
Pesticide, Insecticide, Herbicide or Plant Growth Modifying Agent |
0.01 to 10 wt% |
Surfactant |
0 to 5 wt% |
Dyes |
0 to 20 wt% |
Thickeners/Stabilizers/Co-surfactants/Gel Inhibitors/ Defoamers |
0 to 25 wt% |
Antifreeze |
0.01 to 50 wt% |
Dialkylmalamide |
[0034] A typical water-based fountain solution composition for planographic printing would
comprise the following components:
Water-Based Fountain Solution |
0.05 to 10 wt% |
Film formable, water soluble macromolecule |
1 to 25 wt% |
Alcohol, glycol, or polyol with 2-12 carbon atoms, water soluble or can be made to
be water soluble |
0.01 to 20 wt% |
Water soluble organic acid, inorganic acid, or a salt thereof |
30 to 70 wt% |
Water |
0.01 to 5 wt% |
Dialkylmalamide |
[0035] A typical water-based adhesive composition to which the dialkylmalamide surfactants
of the invention may be added would comprise in an aqueous medium 30 to 65 wt% of
an adhesive composition containing the following components:
Water-Based Adhesive |
50 to 99 wt% |
Polymeric Resin (SBR, VAE, Acrylic) |
0 to 50 wt% |
Tackifier |
0 to 0.5 wt% |
Defoamer |
0.5 to 2 wt% |
Dialkylmalamide |
[0036] A typical water-based photoresist developer or electronic cleaning composition to
which the
N,N'-dialkylmalamide surfactants of the invention may be added would comprise the following
components:
Water-based Photoresist Developer |
0.1 to 3 wt% |
Tetramethylammonium Hydroxide |
0 to 4 wt% |
Phenolic Resin |
88 to 99 wt% |
Water |
10 to 5000 ppm |
Dialkylmalate |
[0037] Examples 1-3 illustrate the synthesis of various N,N'-dialkylmalamides of this invention.
All N,N'-dialkylmalamides were synthesized and then characterized by Nuclear Magnetic
Resonance (NMR) spectroscopy. All malamides prepared ranged from 85% to >99% pure.
Example 1
[0038]

[0039] N,N'-Di-
iso-butyl DL-malamide was prepared by the reaction of
iso-butylamine with diethyl DL-malate. To a round-bottomed flask were added diethyl DL-malate
(5.229 g, 1 eq) and
iso-butylamine (14.058 g, 7 eq). The clear light yellow solution was stirred for 24 hours
at room temperature, after which point a white solid had precipitated from solution.
The solid was filtered, washed with hexane (3x25 mL), and dried under vacuum (1.96
g, 29% yield). The product was >99% pure as determined by NMR analyses.
Example 2
[0040]

[0041] N,N'-Di-
iso-pentyl DL-malamide was prepared by the reaction of
iso-pentylamine with diethyl DL-malate. To a round-bottomed flask were added diethyl
DL-malate (20.013g, 0.1052 mole, 1 eq) and
iso-pentylamine (27.778 g, 3.03 eq). The clear light yellow solution was stirred for
20 hours at room temperature prior to the removal of the excess amine under vacuum
with heating. A white waxy solid was obtained. The solid was triturated with hexane
(4x100 mL), and the product was filtered through a glass frit after each trituration.
Finally, the material was transferred to a round-bottomed flask and the white solid
was dried under vacuum for one hour while heating (<100°C) to remove any residual
amine and hexane (28.99 g, ~100% yield). The product was ~100% pure as determined
by NMR analyses.
Example 3
[0042]

[0043] N,N'-Di-2-ethylhexyl DL-malamide was prepared by the reaction of 2-ethylhexylamine
with diethyl DL-malate. To a round-bottomed flask were added diethyl DL-malate (10.009
g, 1 eq), methanol (31 mL), and 2-ethylhexylamine (13.602 g, 2.00 eq). The clear light
yellow solution was stirred for 7 days at room temperature and then the methanol and
ethanol were removed
in vacuo. The concentrated reaction mixture was refluxed at 70°C for 8 hours. The remaining
ethanol was removed
in vacuo to yield a clear, amber-colored liquid (8.77 g, 47% yield). The product was ~85-90%
pure; half amide/half esters comprised the balance of the product mixture as determined
by
1H and
13C NMR and GC/MS analyses.
Examples 4-6
[0044] Saturated solutions of the materials of Examples 1-3 in distilled water were prepared.
After shaking the solutions for ~24 hours, the undissolved material was removed
via filtration. Equilibrium surface tension data were obtained using the Wilhelmy plate
method, described in L. Wilhelmy,
Ann. Phys. 1863, 119, 177.
[0045] The limiting equilibrium surface tension data are provided in Table 1. The limiting
surface tensions represent the lowest surface tensions in water which can be achieved
for a given surfactant regardless of the amount of surfactant used and is used to
evaluate the effectiveness of a surfactant. Lower surface tensions would allow for
the elimination of defects upon application of a formulation onto low energy surfaces.
Table 1
Example |
Compound |
Limiting EST (dyne/cm) |
Concentration of Surfactant in Solution |
|
Water |
72.1 |
-- |
4 |
Di-isobutyl DL-malamide (Ex 1) |
51.3 |
<1.0 wt.% |
5 |
Di-isopentyl DL-malamide (Ex 2) |
42.9 |
<0.4 wt.% |
6 |
Di-2-ethylhexyl DL-malamide (Ex 3) |
38.5 |
<0.1 wt.% |
[0046] The data in Table 1 illustrate that various N,N'-dialkylmalamides have the ability
to reduce the surface tension of an aqueous composition. Examples 4-6 demonstrate
that N,N'-dialkylmalamides containing branched alkyl groups of 4 to 8 carbon atoms
each exhibited surface tension values of less than 52 dyne/cm at a concentration of
≤1 wt% in water at 25°C. N,N'-di-isopentyl DL-malamide and N,N'-di-2-ethylhexyl DL-malamide
are particularly effective at lowering the equilibrium surface tension of water. Therefore,
the N,N'-dialkylmalamides of this invention which contain branched alkyl groups with
5-8 carbon atoms are the most preferred for the reduction of surface tension in water-based,
organic compound containing compositions, including waterborne coatings, inks, adhesives,
fountain solutions, agricultural formulations, and electronic chemical formulations.
However, ultimately the choice of N,N'-dialkylmalamide will depend upon the application.
Examples 7-8
[0047] The foaming properties of aqueous solutions of N,N'-di-
iso-pentyl DL-malamide (Ex 2) and N,N'-di-2-ethylhexyl DL-malamide (Ex 3), were examined
using a procedure based upon ASTM D 1173-53. In this test, a 0.1 wt% aqueous mixture
of the surfactant was prepared, any undissolved solids were filtered off, and the
filtrate was added from an elevated glass pipette to a glass receiver containing the
same filtrate. The foam height was measured at the completion of the addition ("Initial
Foam Height") and the time required for the foam to dissipate at the air-liquid interface
("Time to 0 Foam") was recorded. This test provides a comparison between the foaming
characteristics of various surfactants. In general, in coatings, inks, adhesives,
fountain solution, agricultural, and electronic chemical formulations, foam is undesirable
because it complicates handling and can lead to coating and print defects, and to
inefficient application of agricultural materials or electronic chemicals.
Comparative Examples 9-10
[0048] The foaming properties of 0.1 wt% solutions of two representative nonionic surfactants,
a commercial nonylphenol 15 mole ethoxylate surfactant and a commercial C8 alkyl glucoside
surfactant were examined using the procedure based upon ASTM D 1173-53.
[0049] The results for the
N,N'-dialkylmalamides of Examples 2 and 3 are reported in Table 2. A drawback to the use
of many conventional surfactants in coatings, inks, adhesives, fountain solutions,
agricultural formulations, and electronic chemical formulations is the formation of
considerable quantities of long-lasting foam in these systems. For such applications,
it is desired that a surfactant form as little foam as possible and that any foam
which forms dissipates quickly. The data in Table 2 show that the compounds of this
invention formed very little initial foam and that the foam which formed dissipated
very quickly. In addition to their ability to reduce the surface tension of organic-containing
aqueous systems, N,N'-dialkylmalamide surfactants have desirable foam properties with
respect to their use in coatings, inks, adhesives, fountain solutions, agricultural
formulations, and electronic chemical formulations.
Table 2
Ex |
Surfactant |
Initial Foam (cm) |
Foam after 5 min (cm) |
Time to zero foam |
7 |
Di-isopentyl DL-malamide (Ex 2) |
1.4 cm |
0 |
35 sec |
8 |
Di-2-ethylhexyl DL-malamide (Ex 3) |
1.5 cm |
0 |
~2 sec |
9 |
Nonylphenol 15 mole ethoxylate |
5 cm |
4 cm |
>5 min |
10 |
C8 Alkyl glucoside |
1.9 cm |
1.0 cm |
37 min |
STATEMENT OF INDUSTRIAL APPLICATION
[0050] The invention provides compositions suitable for reducing the equilibrium surface
tension in water-based coating, ink, adhesive, fountain solution, agricultural, electronic
cleaning and photoresist developer compositions.
1. In a method for applying a coating of a water-based composition to a surface to partially
or fully coat the surface, the composition containing an inorganic or organic compound
and an effective amount of a surfactant for reducing the equilibrium surface tension
of the composition, the improvement which comprises employing as the surfactant an
N,N'-dialkylamide of malic acid of the following structure:

where R
1 and R
2 are C4 to C10 alkyl groups.
2. The method of Claim 1 in which at least one of R1 and R2 is a branched C4 to C10 alkyl group.
3. The method of Claim 1 in which the water-based composition is selected from the group
consisting of aqueous organic coating, ink, adhesive, fountain solution, agricultural
and electronics cleaning compositions and the dialkylmalamide is present at 0.001
to 20 wt% of the water-based composition.
4. The method of Claim 3 in which an aqueous solution of the dialkylmalamide demonstrates
an equilibrium surface tension of less than 52 dynes/cm at a concentration of no more
than 5 wt% in water at 25°C according to the Wilhelmy plate method.
5. The method of Claim 1 in which R1 and R2 are the same.
6. The method of Claim 5 in which R1 and R2 are a branched C4 alkyl group.
7. The method of Claim 5 in which R1 and R2 are a branched C5 alkyl group.
8. The method of Claim 5 in which R1 and R2 are a branched C8 alkyl group.
9. The method of Claim 5 in which the alkyl groups are isobutyl.
10. The method of Claim 5 in which the alkyl groups are isopentyl.
11. The method of Claim 5 in which the alkyl groups are 2-ethylhexyl.
12. An aqueous composition comprising in water an inorganic compound which is a mineral
ore or a pigment or an organic compound which is a pigment, a polymerizable monomer,
an oligomeric resin, a polymeric resin, a detergent, a herbicide, an insecticide,
a fungicide, or a plant growth modifying agent and an effective amount of an N,N'-dialkylamide
of malic acid of the following structure for reducing the surface tension of the composition:

where R
1 and R
2 are C4 to C10 alkyl groups with at least one of R
1 and R
2 being a branched C4 to C10 alkyl group.
13. The aqueous composition of Claim 12 in which an aqueous solution of the dialkylmalamide
demonstrates an equilibrium surface tension of less than 52 dynes/cm at a concentration
of ≤5 wt% in water at 25°C according to the Wilhelmy plate method and the dialkylmalamide
is present at 0.01 to 10 wt% of the aqueous composition.
14. The aqueous composition of Claim 12 in which R1 and R2 are branched C4 alkyl groups.
15. The aqueous composition of Claim 12 in which R1 and R2 are branched C5 alkyl groups.
16. The aqueous composition of Claim 12 in which R1 and R2 are branched C8 alkyl groups.
17. The aqueous composition of Claim 12 in which both R1 and R2 are C5-C10 branched alkyl groups.
18. The aqueous composition of Claim 14 in which the alkyl groups are isobutyl.
19. The aqueous composition of Claim 15 in which the alkyl groups are isopentyl.
20. The aqueous composition of Claim 16 in which the alkyl groups are 2-ethylhexyl.
21. The composition of Claim 12 which is an aqueous organic coating composition comprising
in an aqueous medium 30 to 80 wt% of a coating composition which comprises the following
components
0 to 50 wt% pigment dispersant, grind resin or mixtures thereof;
0 to 80 wt% coloring pigment, extender pigment, anti-corrosive pigment, other pigment
types or mixtures thereof;
5 to 99.9 wt% water-borne, water-dispersible or water-soluble resin or mixtures thereof;
0 to 30 wt% slip additive, antimicrobial agent, processing aid, defoamer or mixtures
thereof;
0 to 50 wt% coalescing or other solvent;
0.01 to 10 wt% surfactant, wetting agent, flow and leveling agents or mixtures thereof;
and
0.01 to 20 wt% dialkylmalamide.
22. The composition of Claim 12 which is an aqueous ink composition comprising in an aqueous
medium 20 to 60 wt% of an ink composition which comprises the following components
1 to 50 wt% pigment;
0 to 50 wt% pigment dispersant, grind resin or mixtures thereof;
0 to 50 wt% clay base in a resin solution vehicle;
5 to 99 wt% water-borne, water-dispersible or water-soluble resin or mixtures thereof;
0 to 30 wt% coalescing or other solvent;
0.01 to 10 wt% processing aid, defoamer, solubilizing agent or mixtures thereof;
0.01 to 10 wt% surfactant, wetting agent or mixtures thereof; and
0.01 to 20 wt% dialkylmalamide.
23. The composition of Claim 12 which is an aqueous agricultural composition comprising
in an aqueous medium 0.01 to 80 wt% of an agricultural composition which comprises
the following components
0.1 to 50 wt% a herbicide, insecticide, plant growth modifying agent or mixtures thereof;
0.01 to 10 wt% surfactant;
0 to 5 wt% dye;
0 to 20 wt% thickener, stabilizer, co-surfactant, gel inhibitor, defoaming agent or
mixtures thereof;
0 to 25 wt% antifreeze; and
0.01 to 50 wt% dialkylmalamide.
24. The composition of Claim 12 which is an aqueous fountain solution composition comprising
the following components
0.05 to 10 wt% film formable, water soluble macromolecule;
1 to 25 wt% alcohol, glycol, or polyol with 2-12 carbon atoms which is water soluble
or can be made water soluble;
0.01 to 20 wt% water soluble organic acid, inorganic acid, or a salt thereof;
30 to 70 wt% water; and
0.01 to 5 wt% dialkylmalamide.
25. The composition of Claim 12 which is an aqueous adhesive composition comprising in
an aqueous medium 30 to 65 wt% of an adhesive composition which comprises the following
components
50 to 99 wt% polymeric resin;
0 to 50 wt% tackifier;
0 to 0.5 wt% defoamer; and
0.5 to 2 wt% dialkylmalamide.
26. The composition of Claim 12 which is an aqueous electronics cleaning composition comprising
in an aqueous medium the following components
0.1 to 3 wt% tetramethylammonium hydroxide;
0 to 4 wt% phenolic compound; and
10 to 10,000 ppm dialkylmalamide.